Women in the U.S. may be subjected to unnecessary tests following a mammogram, according to the results of a new study. Researchers writing today in the Journal of the American Medical Association (JAMA) report that American women are recalled for further tests, such as biopsies, twice as often as their British counterparts. Yet breast cancer detection rates in the U.S. and the U.K. are about the same.

Rebecca Smith-Bindman of the University of California at San Francisco and her colleagues looked at data on women ages 50 and older in the U.S. and Britain who underwent 5.5 million mammograms over a four-year period. Of these women, 27, 612 were diagnosed with breast cancer within 12 months of being screened.

The team believes that the lower recall rates in the U.K. can be attributed in part to the centralization of British screening--the National Health Service runs a program that provides nearly all mammographic examinations for women aged 50 and up. Also, the threat of malpractice lawsuits in the U.S. may make American radiologists overly cautious.

"Screening women aged 50 to 69 years biennially and reducing recall rates could substantially decrease the cost of mammography, as well as associated anxiety caused by false-positive diagnoses," the authors write. "Efforts to improve U.S. mammographic screening should be targeted to lowering the recall rate without substantially lowering the cancer detection rate." --Kate Wong